Cardiovascular disease is the leading cause of death in women in the United States, accounting for nearly 39% of all female deaths. Yet only 13% of women perceive heart disease as their greatest health problem. Accurately identifying women "at risk" is essential for the prevention of cardiovascular disease morbidity and mortality. Although the prevalence of cardiovascular disease risk factors is highest in overweight and obese women, a significant number of normal-weight women (BMI <25 kg/m2) have insulin resistance and risk factors. These women are called metabolically obese normal-weight (MONW). MONW individuals have insulin resistance and may present a clustering of cardiovascular disease risk factors despite a normal body weight. However, because these women are normal weight, they are not aware that they are at risk. Therefore, the overall aim of this proposal is to establish specific metabolic and physical characteristics that distinguish MONW from non-MONW young Hispanic women. The main hypothesis is that MONW young Hispanic women, characterized by insulin resistance, will have more cardiovascular disease risk factors, higher percent body fat, central fat distribution and lower levels of physical activity and cardio-respiratory fitness compared to non-MONW young Hispanic women. To do this we will recruit 100 normal-weight Hispanic women 18-39 years of age and divide them into two groups, MONW and non-MONW, based on insulin resistance. We expect 15-18% of the women tested to be MONW. Subjects will be tested for serum levels of insulin, glucose, lipids and inflammatory markers by fasting blood draw, body composition and body fat distribution by dual X-ray absorptiometry and waist circumference, glucose tolerance by oral glucose tolerance test, cardio-respiratory fitness by aerobic capacity test, and daily physical activity by accelerometer worn over seven days. Results from this study will identify distinguishing characteristics of MONW young Hispanic women and will contribute to the understanding of factors that increase cardiovascular disease risk in this population. Identification and early treatment of these at-risk women would have a tremendous impact on quality of life, severity of disease at diagnosis and overall public health.